The Enrollment Survey is completed by all twin pairs to enroll in the Washington State Twin Registry. Twins are asked to provide their cotwin’s contact information on the survey. This allows us to invite their cotwin to participate as well. The survey provides researchers with basic health information which they can use to publish papers, apply for grants, and recruit for studies.

The survey has evolved over the years. New questions that may be of interest to researchers have been added. Questions which do not provide researchers with the best information have been changed or removed. For example, the first Enrollment Survey, which was sent out from 2002-2007, included a question about race that only allowed respondents to choose one answer and included Hispanic/Latino as a race option. This question was updated in 2007 to reflect current NIH & US Census guidelines for reporting race and ethnicity. It now allows respondents to choose more than one answer and to report ethnicity (Hispanic/Latino) separately.